Knuckles the Echidna is a sixteen-year old red echidna from the Sonic series and is the guardian of the Master Emerald on Angel Island. He competed against Mario and others in Olympic events in Mario & Sonic at the Olympic Games. In this game, Knuckles acts as a power-type character, meaning he excels at games that require brute strength, such as Hammer Throw or Javelin Throw. He is also the fastest of the Power characters. In Mario & Sonic at the Olympic Games, he was voiced by Dan Green, who also voiced Vector the Crocodile in that game. He is currently voiced by Travis Willingham.

Knuckles reappears in the game's sequel as a power character again. In the DS version's story mode, Knuckles is found in Frostown, after Mario and Sonic defeats him in a mission, he'll join them and help them in their quest to free the Snow Spirits.

"Knuckles is an echidna that shows exceptional versatility despite his overall strength in Power events. He'll perform best at events like throwing and rowing, but can also provide solid competition in many other competitions that aren't as power-based."

A powerful red echidna also known by his full name, Knuckles the Echidna. Knuckles resides on Angel Island, where he guards the Master Emerald. Both friend and rival of Sonic, Knuckles is a martial-arts expert who can break through rocks with his spiked fists. In addition, he can climb walls and use the wind to glide through the air.

"Knuckles the Echidna has been friend and foe to Sonic for years. He has protected the Master Emerald on Angel Island, but now has his eye on a new prize: being #1 in the Olympic Winter Games! Powerful and determined, Knuckles will be going for gold with his Screw Driver ability on the Wii and DS, and Spiral Uppercut ability on the DS."